Title

Author

Date Approved

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biology

Committee Member

Peter Bednekoff, PhD, Chair

Committee Member

Steve Francoeur, PhD

Committee Member

Mike Kielb, M.Sc.

Abstract

Common terns are declining in the Great Lakes region and represent a population relatively distinct from that of eastern North America. On an artificial site, I studied the substrate and vegetation preference and productivity of nesting terns at two scales: general habitat and nest-site. Terns nested later and less successfully in large river rock (13 to 25-cm diameter) compared to more diverse substrate and limestone (2.5-5.0 cm) when it was free of dead vegetation. Within a habitat, terns chose to nest where substrate was most diverse in rock size, soil, and non-vegetative debris. Percent standing cover did not affect hatching success, but did have a positive effect on fledging success. I monitored predation and nocturnal desertion and determined the behavior was variable between pairs and the detection of a black-crowned night heron (Nycticorax nycticorax) predating chicks at night did not lengthen the nocturnal nest desertion time of common terns.